The present invention is related to a CCD and CMOS image pickup module, and more particularly to an image pickup module in which by means of the high precision of the surface of the package of the image sensor, the axis of the lens will not deflect from the image sensor so that image deflection can be avoided.
FIG. 6 shows a conventional CCD image pickup module. A CCD image sensor 91 and relevant electronic circuit 92 are laid on a circuit main board 90. A coupling transistor is disposed at the center of the image sensor 91. Two fixing holes 93 are formed on two sides of the image sensor 91. Screws 96 are passed through the fixing holes 93 and screwed into two thread holes 942 on two sides of a lens seat 94 to lock the lens seat 94 on the circuit main board 90. A lens 95 is screwed in the lens seat 94.
The electronic circuit 92 is laid over the circuit main board 90. The electronic circuit 92 itself has a certain thickness. In addition, after soldered, the soldering points will protrude beyond the circuit main body 90. Therefore, there is a difference in height between the electronic circuit 92 and the soldering points. As a result, when locking the lens seat 94, the axis 951 of the lens will be deflected from the sensor center 911 of the image sensor 91 (as shown in FIG. 8 ). This leads to image deflection and distorts the image.
Moreover, when fixing the lens seat 94, the image sensor 91 is enclosed by the lens seat 94. Therefore, it is hard to ensure that the lens 95 is lined up with the sensor center 911 of the image sensor 91 (as shown in FIG. 7). It is known that after focused by the lens 95, the central part of the image will have higher resolution, while the peripheral part of the image will be relatively distorted. In addition, only the image falling onto the central image pickup unit 911 of the image sensor 91 will be picked up and presented. In the case that the axis 951 of the lens 95 is displaced from the sensor center of the image sensor 91, the relatively distorted image will fall onto the image pickup unit 911 so that the image will have an image deflection and can be hardly clearly presented.
In addition, two sides of the lens seat 94 are formed with thread holes 942 for the screws 96 to lock the lens seat 94. Therefore, the volume of the lens seat 94 cannot be reduced. This results in inconvenience in design and use of the product.